the 'midwit theory' also explains part of this. the people with less education will be suspicious of the vaccine because it represents an unknown of such a scope. the truly intelligent and curious will go into it with multiple hypotheses in mind - either the vaccine is safe, it isn't safe, or it's a mixed bag, and then as they read more and more about the vaccine they'll sort the data into the respective bins and take stock and weigh the evidence every so often at interval and come to their own independent conclusion on the matter. the midwits however are the ones who wind up brainwashed, many of them populate the higher education institutions these days... the faith they have in consensus, the appeal to authority, the belief that in general there are no conspiracies. in a way it's better to be uneducated than to be one of these folks.